The invention concerns an electromedical implant comprising a telemetry device for the exchange of data with an external apparatus and more particularly to a cardiac pacemaker comprising such a telemetry device.
In conventional electromedical implants with a telemetry device for the exchange of data with an external apparatus, such as, for example, cardiac pacemakers, defibrillators, cardioverters or other electronically actuated or controlled implants, the energy for transmission and reception for the telemetry device, including a transmitting device and a receiving device, is usually taken from a previously charged buffer capacitor.
In such a system, if transmission and reception follow in direct succession, the buffer capacitor has to be charged up to a high voltage to have sufficient voltage ready for the second procedure after the voltage drop resulting from the first procedure. Accordingly, the components involved (charge pump, capacitors, voltage regulator) must be designed for a voltage strength which would otherwise not be required in the implant. Such high voltage components increase the implant production costs. In addition, energy is lost because of the poor efficiency of voltage multiplication, which is a problem given the severely limited energy supply in an implant of that kind.
Accordingly, the need exists for an telemetry capable electromedical implant having lower production costs and which has lower energy requirements.
The invention is directed to an electromedical implant comprising a telemetry device for the exchange of data with an external apparatus where the telemetry device comprises a transmitting device and a receiving device, characterized in that separate energy storage devices are provided for the transmitting and receiving devices.
In such an apparatus, lower production costs and lower energy requirements are obtained if separate energy storage means are provided for the transmitting device and the receiving device, because the separate energy storage means only have to be charged to the voltage necessary for the single procedure involved. Furthermore, less energy is lost through voltage multiplication. Finally, the energy consumption involved in transmission does not influence the energy supply for reception and vice versa so that the procedures can occur in immediate succession, which is desirable for a bidirectional communication protocol. In this respect, an electromedical implant according to the invention is a particularly advantageous in the area of long-range high-frequency telemetry.
In one alternative embodiment, the individual energy storage means are formed by a buffer capacitor. In such an embodiment, the buffer capacitors may be of different sizes and the size of the buffer capacitors are matched to the procedure which is to be supplied thereby, e.g., if a transmission procedure should requires more power than a reception procedure.
In another alternative embodiment, the buffer storage means may be designed such that they can both be charged at the same time depending on the requirements involved in unidirectional or bidirectional operation of the telemetry. In this respect, the buffer storage means are preferably charged immediately prior to a transmission procedure or a reception procedure in order to avoid the energy losses due to loss currents that can occur during relatively long periods of maintaining the charged state.
In still another alternative embodiment, one energy storage means is utilized as a safety reserve for the other energy storage means to improve transmission reliability. In such an embodiment, it is possible for the energy supply to be better utilized because, there would be no need to keep an additional safety reserve capacitor available for use after draining the first energy storage means.
In yet another alternative embodiment, it is possible to implement changes in the utilization of energy from a particular energy storage means using the circuit according to the invention. For example, in one exemplary embodiment, after draining the transmission energy storage means, the circuit could instruct the reception energy storage means to provide power for a renewed safety data transmission operation.